1. Field of the Invention
The invention relates to methods of preparing invertase from yeast.
2. Brief Description of the Related Art
Invertase is contained within the cells of various yeasts. In order to obtain the enzyme, which is employed on the industrial scale in the foodstuffs industry, it is necessary to disrupt the yeast cells. This is followed by removal of the cell detritus and undesired proteins.
Invertase is distinguished by an above-average resistance to heat and low pH values. Based on this, a process for obtaining invertase has already been proposed, in which a heat treatment is carried out at a pH of 5.0, but this yields a purification factor of only 2. It is therefore not surprising that the method of obtaining invertase in practice does not make use of this process which was proposed as long ago as 1967; N.P. Neumann and J.O. Lampen, Biochemistry 6 (1967), 468-475 . On the contrary, the classical working up of invertase provides for two acetone-precipitation steps; cf., for example, Ullmanns Enzyklopadie der technischen Chemie; H. Vetter et al. "Enzyme", in: Ullmanns Enzyklopadie der technischen Chemie, Vol. 10, pp. 475-561 Verlag Chemie, Weinheim, 1975.
A process proposed in a Japanese patent (S. Takai et al., Japan. Patent, JP 45/9824 [70/9824], Apr. 9, 1970) also has a similar procedure:
In this case 30-hour cell lysis and acid treatment at pH 4.5 are followed by filtration and then acetone precipitation and finally extraction. A process proposed by other authors (E. Matulaityte and V. Avizienis, Matr. Biokhim. Konf. Pribalt. Resp. B. SSR, 5th, Volume 2, 14-15, Editor I.K. Sibul Akad. Nauk. Est. SSR: Tallin, USSR) is also very similar to this process.